Heater inserter



Jan. 10, 1956 H. w. ROEBER ETAL 2,729,877

HEATER INSERTER Filed Feb. 20, 1948 3 Sheets-Sheet 1 By Henry M Roebefl Their fitter/leg Jan. 10, 1956 H. w. ROEBER ET AL HEATER INSERTER Filed Feb. 20, 1948 3 Sheets-Sheet 5 I N V EN TORJ Stanley (1 Garlner BY Henry /V. Roebel' United States Patent HEATER INSERTER Henry W. Roeber and Stanley J. Gartner, Emporium,

Pa., assignors to Sylvania Electric Products Inc., a corporation of Massachusetts Application February 20, 1948, Serial No. 9,844

12 Claims. (Cl. 2925.19)

This invention is concerned with the manufacture of electron tubes and more particularly to methods and apparatus for the assembly of a filamentary heater into a tubular cathode sleeve. The resulting indirectly heated cathode constitutes one electrode that is then assembled with others to provide tubes of the kind widely used in radio receivers.

Filamentary heater wire, coated with insulation and bent into bundle form, is inserted into cathode sleeves manually according to prevailing practice. This manual operation is a significant item in the assembly of. tubes where manual operations are important cost factors, and where even skilled handling of the materials may yield defective radio tubes that must be discarded. Furthermore, the heater bundle within the cathode sleeve of a manual assembly must by design be relatively loose for practical reasons whereby the cathode is likely to be slow in starting; whereas a superior cathode with a tightly fitted heater can be realized with a successful machine and mechanical assembly technique. The need for an automatic machine for assembling bundled heater wire within cathode sleeves has been recognized, but proposed apparatus has so far failed to be generally acceptable.

One type of cathode sleeve is in the form of an externally cylindrical tube formed of sheet metal, the longitudinal edges of the metal blank being joined in a lock seam. The end surface of the lock seam within the cathode tube introduces a complication in the problem of heater insertion. The heater wire is likely to abut the lock seam during its endwise approach to the hollow cathode, and if it is thrust further the heater wire is likely to become hopelessly deformed.

An object of the present invention is to devise a method and apparatus for inserting heaters into cathode sleeves, whether of the seamless or lock-seam variety. In achieving this purpose in the illustrative embodiment of the invention detailed below, the heater is formed as a bundle of wire which is oscillated slowly about its longitudinal axis as it approaches the cathode sleeve endwise, and a rapid circular or precessional motion is applied to the leading end of the bundle. By virtue of these two motions, the heater filament, guided by a funnel, is assured admission into the end of a lock-seam or a seamless cathode sleeve. The circular motion of the end of the filament is a special kind of vibration that packs the several portions of the filamentary heater bundle together and promotes endwise travel of the bundle down the constricted guide passage of the funnel and into the cathode sleeve. The oscillation of the bundle of heater wire about its longitudinal axis is effective to remove any portion of the bundle laterally that may abut the lock seam, but other ends of the bundle that previously entered the cathode sleeve are not thereby caused to abut the end of the lock seam. The simultaneous application of all these motions is a further fea ture of the apparatus embodying the invention.

The invention will be better understood, together with further features of novelty, from the following detailed description of an illustrative form of apparatus, which operates according to the novel method. In the accompanying drawings:

Fig. 1 is a plan view of the entire illustrative machine with certain parts broken away,

Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1, thereby illustrating the mechanism for oscillating the bundle of heater wire,

Fig. 3 is a fragmentary section from the viewpoint 3-3 in Fig. 2,

Fig. 4 is a sectional view along the line 4-4 of Fig. 1,

Fig. 5 is an enlarged lateral view, partly in section, of the cathode gripper in its position as it engages a cathode supplied by a cathode conveyor,

Fig. 6 is a sectional view along the lines 66 of Fig. 5,

Fig. 7 is a longitudinal section of the chuck or support for carrying the bundle of heater wire,

Fig. 8 is an enlarged view of the operative mechanism, partly in section, showing the heater about to enter the cathode tube,

Fig. 9 is an enlarged fragmentary view of a cathode and heater assembly as it emerges from the machine,

Fig. 10 is a detailed view of the mechanism which moves the advance end of the heater bundle in a small rapid circle, and

Fig. 11 is a transverse sectional view of the cathode, greatly enlarged, showing the cylindrical exterior of the cathode with the lock-seam occupying part of the hollow interior of the cathode.

Referring now to Fig. 1, cathode sleeves are advanced stepwise by conveyor 20, and received by gripper and transfer mechanism 22 that is reciprocable across conveyor 20; and chuck assembly 24 receives the bundled filaments and transports them endwise into the cathode sleeves. A mechanism 26 is efiective to oscillate each bundled heater slowly during its endwise advance toward a cathode sleeve, and the leading end of the heater bundle is rapidly moved in a small circle by the mechanism generally designated 28.

Supply conveyor 20 comprises a stationary plate 30 that is transversely grooved to receive a series of cathode sleeves. At opposite sides of plate 30 are grooved feed rails 32, 34 which are operated by cams 36 and 38 on shaft 39 in a four-motion path to lift the cathodes from their notches in plate 30, advance them one step, lower them into the respective succeeding grooves in plate 30, and withdraw to renew the four-motion feeding cycle. Rails 32 and 34 are joined to inverted channel 40 (see Fig. 4) and supported for lengthwise sliding along the top of vertically reciprocable T-shaped member 42 which slides in vertical guide 434 and is alternately lowered by spring 48 and raised by cam 38 and antifriction cam-follower 46. Channel 40 is longitudinally slotted to accommodate cam-follower 46. Channel 40 has a lateral depending arm 50 carrying camfollower 52 maintained in engagement with cam 36 by tension spring 54. During each machine cycle, during which a heater is inserted into a cathode sleeve, feeder 20 advances the supply of cathode sleeves one step. At first cam 38 raises T-shaped member 42 and thereby raises the feed rails 32 and 34. Thereafter cam 36 with its cam follower 52 is effective to advance the feed rails one step. Next, the T-shaped member is lowered under influence of tension spring 48 as controlled by cam 38, and finally the feed rails are retracted by spring 54 under control of cam 36.

As can be seen from Figs. 5 and 6 the feed rails of cathode feeder 20 are effective to deliver cathodes successively to jaws 56 and 58 of the cathode transfer mechanism. During the advance of the feed rails, jaws 56 and 58 are opened and because of their arcuate travel during opening they are clear of the advancing path of the cathode sleeves. The leading end of feed rail 32 is thinned out to provide an extension 60 for supporting h for mo t a h slee hile prg id ns c a an for jaws 56 and 58.

ews 5. and 58 a e p d w th up ard e ensions carrying antifriction rollers 62 and 64, respectively. Jaw 56 is pinned to a shaft 66 which at one end is rotatably supported in block 68. law 58 is pinned to sleeve 70 which is rotatable in block .68 and which functions additionally as a second bearing for shaft 66. Collar 72 is secured to a projecting portion of shaft 66, and between sleeve 70 and collar 72 a torsion spring 74 encircles the shaft and urges jaws 56 and 58 toward mutual engagement. When closed, these'jaws are centered by aportion of block 68 depending between rollers 62and 64 (Fig. 6).

Block 68 is carried by shaft 76 for horizontal reciprocation (Fig. 4) within stationary bearings 78 and 80. When shaft 76 and block 68 have been retracted (iby mechanism to be described) antifriction rollers 62 and 64 underlie a bifurcated operator 82 that is lowered to separate jaws 56 against the force of torsion spring 74. Operator 82 is vertically reciprocable in slide bearing 84 and carries an antifriction roller 86. One end of a lever 88 (Fig. l) underlies roller 86; this lever is pivoted intermediate its ends; and at its opposite end lever 88 carries cam follower 90 which underlies cam 92 on shaft 39. Tension spring 94 is attached to operator 82 to urge it against lever 88, tourge lever 88 toward cam 92, and to overcome torsion spring 74 in opening jaws 56, 58.

As controlled by cam 92 and lever 88, spring 94 urges operator 82 against rollers 62 and 64 for separating jaws 56 and 58 against the effect of torsion spring 74. When jaws 56 and 58 are to be closed, cam 92 acts on roller 90, lever 88 and antifriction roller 86 to raise operator 82 from rollers 62 and 64. Torsion spring 74 is then effective to close the jaws. It is notable that a 'bare minimum of mechanism is carried by block 68. Heavy jaws and mechanisms of large mass tend to reduce the permissible speed of the machine and to damage the frail cathode sleeves as each reaches a stop to be described.

After a cathode sleeve has been gripped by jaws 56 and 58 it is to be advanced endwise into position for receiving a bundle of filamentary heater wire. The timing of feed rails 32 and 34 is such that, during the time they are lowered out of the path of the cathode jaws, block 68 and shaft 76 are thrust forward to bring the free end of the cathode sleeve into a fixed funnel-shaped sleeve support 96.

following cam-and-spring mechanism is provided. In

Figs. 1 and 4 block 98 is secured to shaft 76 and has a depending portion which closely embraces and slides along a gib 100. This prevents the rocking of shaft 76 about its axis and, with the depending portion of block 68 between rollers 62 and 64, maintains jaws 56, 58 in alignment with funnel 96- At ne side of block 98 a cord 102 is secured which is wound about bobbin 104 by torsion spring 106, both spring 106 and bobbin 104 being arranged on shaft 108. :One end of torsion spring 106 is fixed to a portion of the machine frame while the other end of that spring is secured to collar 110 that is pinned to shaft 108. It is thus apparent that shaft 76 and the cathode-engaging jaws 56, 58 are urged toward the right in Fig. 4 by the torsion spring and the tensioning cord, the tensioning mechanism adding only insignificantly to the mass associated with the cathode jaws. This is a factor contributing materially to sneces'sful operation of the cathode-handling mechanism, for a hea y j -as embl ou f rm thod S ee e bei g t ru n funnel 96.

Block 98 carries an antifriction roller 112 on the side opposite the foregoing tensioning mechanism. Cam 11-6 on shaft 39 acts on cam follower 118 carried by lever 114 to bear on roller 112 and operate shaft 76 positively toward the left and to control its travel toward the right as influenced by torsion spring 106.

Cams 92 and 116 are effective in proper timed sequence to lower operator 82 for opening the cathodeengaging jaws when a completed cathode is to be released and for closing them on a cathode sleeve supplied by conveyor 20, and then to reciprocate jaws 56, 58 to the right in positioning a cathode sleeve for receiving .a bundle of heater wire. The operation of the jaws" is timed with relation to the cams 36 and 38 so'that' a completed cathode is released before rails 32,, 34. reach the jaws; and the timing is such that the jaws remain properly positioned and in condition to receive a cathode sleeve following an elevated forward stroke of the feed rails. Completed cathodes are removed from the machine by a suitably driven endless belt 120.

A length of heater wire, folded endwise to constitute a bundle, is inserted into each cathode sleeve by the mechanism generally designated 24. This mechanism includes a form of chuck 122 which is operated for auto.- matically receiving bundles of heater wire as from .a so-called spade-Winding machine which is well known and forms no part of the present invention. As will be seen from Figs. 1 and 4, chuck 122 is supported on a horizontally reciprocable carriage 124 and is swingably mounted on vertical post 126 which has pinion 128'fixed to its lower extremity. Carriage 124 is slidable along fixed rods 130 and is reciprocated by cord 132, operated by a cam and cam follower not shown, and by a tensioning cord 134.

Chuck 122 is swung 180 during the alternate reciprocations in order to maintain the chuck opening in position for receiving a spade-wound heater during its travel toward the right, Fig. 4, and for delivering a heater with the projecting ends foremost during reciprocations of carriage 124 to the left. Chuck 122 has a laterally extending arm 136 which engages screw stops 138 and 139 alternately to limit the oscillation of the chuck about the vertical axis. Slidably mounted within carriage 124 is a rack 140 having depending extensions 142 and 143 at its extremities. Below carriage 124 and parallel to rods 130 is a stationary tube 144 containing a tension spring 146. At its ends tube 144 is slotted and pins 14 and which are secured to the extremities of spring 146, project into the path of rack extensions 142 and 143., respectively.

Assuming that a folded filament has just been inserted into a cathode sleeve and carriage 124 commences its return stroke for receiving the next filament bundle, carriage 124 transports the chuck without swivelling until extension 142 engages pin 148. Thereafter rack 140 is resiliently arrested and pinion 128 causes chuck 122 to swivel clockwise. This sweep is continued until arm 13,6 engages stop 138. Thereafter pinion 128, thus locked, forces rack 140 to move with the carriage and causes spring 146 to stretch. During this stroke of carriage 124, a bundle of filament wire is heldin position for entering the chuck. It is fully inserted when the chuck reaches the dotted-line position indicated in Fig. 4. Thereafter chuck 122 is partly withdrawn without oscillation, as carriage 124 moves to the left (Fig. 4) and the return sweep of chuck 122 as limited by stop 139 is enforced by rack extension 143 in engagement with stop 150. During further travel of the carriage, spring 146 is stretchedby lateral extension 143 of the rack while chuck 122 moves the forward travel, the bundled filament is oscillated about its longitudinal axis so that any portion that may abut the lock-seam will be laterally displaced for unobstructed admission into the tubular cavity of the cathode sleeve; and return oscillation of the filament bundle will not again cause abutting engagement of that portion of the filament bundle with the lock-seam because the bundle has advanced during the oscillation. The oscillation is limited to a small part of one rotation, to avoid twisting the bundle of insulated wire.

The details of chuck 122 are shown in Fig. 7. Chuck 122 comprises a body portion 152 having an insert 154 which is provided with air passages 156 and 158 for purposes to be described. Carried externally of insert 154 by ball bearings 160 and 162 is a cylindrical member 164 formed with a funnel 166 and central passage 168 for receiving the bundled filament wire. Internal extension 170 of member 164 fits snugly and rotatably within a bore in member 164 to provide a substantially air-tight coupling between passages 158 and 168.

The bundled filament fits within passage 168 and is oscillated about its longitudinal axis by the following mechanism. in Figs. 1, 2 and 3, a longitudinally reciprocablebar 172 is shown having a friction pad 174 in engagement with the exterior of member 164. Bar 172 is longitudinally reciprocated across the axis of member 164, and completes several cycles of reciprocation during a single insertion stroke of chuck 122. Bar 172 is pivoted at, its right end (Fig. 2) and is pressed against member 164 by tension spring 174. During portions of the cycle when chuck 122 is not advancing for inserting a filament into a cathode sleeve, bar 172 is raised out of contact with cylindrical member 164 by cam 176 on shaft 39. The pivoted end of bar 172 is carried on vertical lever 178 and is oscillated for longitudinally reciprocating bar 172 by motor and reduction gearing unit 180 and coupler 182. This coupler comprises eccentric pin 184 arranged within grooved insert 186 in vertical lever 178. Rotary drive of unit 180 is converted by lever 178 and bar 172 to oscillatory motion of chuck 122 during its heater-inserting stroke.

For packing the loose filament bundle and promoting its admission into the hollow end of a cathode sleeve, a funneled guide or nozzle is provided (see especially Fig. 8) the central axis of which is moved transversely in a small orbital circle at very high speed in comparison to the insertion stroke and in comparison to the oscillation of the bundle about its vertical axis. Thus, it may take two seconds for chuck 122 to complete a heater-insertion stroke, and during that stroke bar 172 may reciprocate six times; whereas the funneled guide for the leading end of the filament bundle may cycle several hundred times during an insertion stroke.

Funneled guide or nozzle 188 has its rear face in sliding contact with sleeve support 96. At its front guide 188 has a conical admission port 190 converging toward bore 192 forming an exit passage the diameter of which is somewhat smaller than the internal diameter of the cathode sleeve. During the high-speed circular travel of guide 188 and the lengthwise approach of chuck 122, the end portions of the filament bundle (terminals T as well as bends B) are forced in funnel portion 190 to converge and enter passage 192. This circular motion reduces frictional resistance of the heater traveling along constricted guide passages, and packs the filament for admission into cathode sleeves whether of the lock-seam variety or the seamless type; and in connection with lockseam cathode sleeves, the circular motion of the guide helps displace filament end-portions that may abut the lock-seam to enable them to enter the cavity of the cathode sleeve.

The mechanism for moving guide 188 in small high speed circles is shown in Figs. 1 and 10, and comprises a drive pulley 194, a belt 196, a driven pulley 198, shaft 200 and eccentric pin 202. This pin (Fig. drives the right end of a horizontal lever 204 in small circles, so that the right end of this lever where guide 188 is carried is also moved in small circles, lever 202 being pivoted at its midpoint from a depending swingable hanger 206. The eccentricity of pin 202 advantageously is about equal to the difference between the internal diameter of a cathode sleeve and the smaller passage 192. For a sleeve of .041 in. internal diameter and a bore 192 of .034 in., a .005 eccentricity is effective.

Referring now to Fig. 8 the sequence of operations will be briefly recapitulated. Chuck 122 in which a bundle of heater wire was previously inserted advances along a straight-line path with the filament bundle projecting. When the portions of the bundle enter conical passage 190 in member 188, the strands forming the bundle are packed together sufficiently to enter constricted passage 192. As the bundle advances further, with reduced frictional resistance due to the circular vibration, the ends of the filament bundle might abut the cathode lock-seam (Fig. 11) except for the rapid circular travel of guide 188 and the relatively slower oscillation of the bundle about its longitudinal axis caused by the oscillation of chuck 122. The cathode is supported during insertion of the heater bundle by a pair of jaws (only one of which 58 is shown in Fig. 8), and by stationary support 96. The jaw assembly is of light-weight construction, for if it were heavy the cathode sleeves would be deformed or crushed upon contact with the back face of nozzle 188.

Previously it was mentioned that chuck 122 incorporates air passages 156 and 158. These communicate with rotary coupler 210, that provides for the 180 swiveling of the heater chuck, and with air line 208. When the heater bundle has been admitted into the cathode sleeve, its insertion is completed by a quick burst of compressed air through the passages described, under control of valve 212 from compressed air supply line 214, as controlled by cam 216 on shaft 39.

When the heater has betn fully inserted as described, chuck 122 commences its return stroke along a straight line followed by its arcuate swing, while jaws 56, 58 withdraw the cathode and heater assembly from stationary guide 96. The jaws are finally opened to drop the assembled cathode on conveyor when fully retracted, and are then in condition to sieze the next cathode sleeve advanced by the four-motion conveyor.

The foregoing detailed embodiment of my invention represents a highly successful illustration of my invention incorporating novel features separately and jointly useful. However it will be understood. that numerous detailed revisions of this embodiment and application and substitution of its components will occur to those skilled in the art, and therefore I desire that the appended claims be given broad interpretation consistent: with the spirit of the invention.

What I claim is:

1. The method of assembling indirectly heated cathodes having a bundle of heater wire within a hollow sleeve.

and comprising the steps of simultaneously compacting said bundle of heater wire, oscillating the bundle relative to said sleeve and about its longitudinal axis, and advancing it endwise toward and into the open end of the cathode sleeve.

2. Apparatus for assembling indirectly heated cathodes comprising means for supporting a cathode sleeve, a carrier for supporting a bundle of heater wire in endwise alignment with a supported sleeve, drive mechanism for causing mutual approach of said sleeve-supporting means and said bundle carrier, means for producing slow relative oscillation between the sleeve and bundle about the common axis of the sleeve and bundle, and a high-speed vibrator mechanism for moving the juxtaposed ends of the bundle and the cathode sleeve in relation to each other.

3. Apparatus of the class described comprising a support for a tube, a reciprocable carrier for a bundle of filamerit material having drive means for advancing the bundle endwise toward the opening of the supported tube, a progressively constricted guide between said tube support and said bundle carrier, and a vibrator for said guide, whereby said bundle is packed together during its advance toward a tube and while so compacted is directed into the tube.

4. Apparatus of the class described comprising a support for a sleeve, a carrier for advancing a bundle of wire endwise toward the end of a supported sleeve, and a mechanism for oscillating said bundle about its longitudinal axis during its approach toward the sleeve.

5. Apparatus of the class described comprising a support for a sleeve, a carrier for advancing a bundle of wire endwise toward the end of a supported sleeve, a guide between said support and said carrier for directing the leading end of the bundle into the exposed end of a cathode sleeve, means for vibrating said guide, and a mechanism for oscillating said carrier and therefore, said bundle about its longitudinal axis during its approach toward the cathode sleeve.

6. A cathode assembling machine comprising a'conveyor for supplying cathode sleeves, a stationary sleeve support, a mechanism for inserting heaters into cathode sleeves in said support, and a transfer mechanism for carrying cathode sleeves individually from said supply conveyor to said support comprising a pair of jaws for gripping a cathode sleeve delivered by said conveyor, a spring for closing said jaws and a mechanism for opening said jaws, and means for reciprocating said jaws to and from said cathode sleeve-support including a spring urging said jaws toward said support whereby a minimum of mass is fixed to said jaws and accompanies a sleeve during transfer toward said support.

7. Apparatus of the class described comprising means for supporting a sleeve, a carrier for supporting a bundle of wire in endwise alignment with a supported sleeve, drive mechanism for advancing said carrier toward said supporting means, a mechanism for oscillating a bundle about its longitudinal axis during its approach toward and into said sleeve and a pneumatic ejector having a passage within said carrier for removing a partly inserted bundle from said carrier and thus for completing the insertion of the bundle into the sleeve.

8. Apparatus of the class described comprising a sleeve support and a coacting inserter for a bundle of wire, said irise'r'ter comprising means for vibrating at least the lead ing portion of a bundle to be inserted into a sleeve relative to said sleeve and a mechanism for concurrently oscillating the bundle about its longitudinal axis.

9. In combination, cathode-supporting means for holding a tubular substantially cylindrical cathode sleeve of predetermined inside diameter and having an open end, with said open end accessible and including means directly supporting said end in predetermined position and with the cylindrical axis of the cathode sleeve in predetermi'ned orientation, a guide separate and distinct from' end of a cathode sleeve and transverse of said oriented axis thereof, the diameter of said circular path being approximately equal to the difference between said predeterminad inside sleeve diameter and said passage exit diameter.

10. The combination of claim 9 including in addition a chuck on the side of said guide opposite to said cathodesupporting means and having an axial passage for receiving a bundled heating filament, supporting mechanism carrying said chuck reciprocably endwise toward and from said passage entrance, said chuck having a rotary bearing coaxial with said passage, and a low-speed oscillating driver operatively connected to said chuck for oscillating the bundled filament slowly about its axis relative to the orbital speed of the guide during the passage of the filament into and through the funnelled guide passage and into a supported cathode sleeve.

11. In combination, cathode-supporting means for holding a tubular substantially cylindrical cathode sleeve of predetermined inside diameter and having 'an open end with the open end in a predetermined position and with the cylindrical axis thereof in predetermined orientation, a guide separate and distinct from all portions of said cathode-supporting means having a movable support constraining motion thereof transverse to the oathode sleeve axis and having a funnelled passage therethrough from a constricted circular exit at one side of the guide to a wide entrance at the opposite side thereof, said constricted exit being opposite the open end of the cathode sleeve in said supporting means, and said exit being smaller in diameter than the inside diameter of the supported substantially cylindrical cathode sleeve, a reciprocable carrier receiving and endwise transporting a bundled multiple-folded heating filament into said passage at the wide entrance thereof and thence therethrough and axially into the cathode sleeve carried by said supporting means, and a high speed vibrator operatively connected to said guide for rapidly vibrating the guide during slow insertion of a heating element by said carrier transversely in relation to the axis of the supported cathode sleeve through a stroke approximately equal to the difierence between the diameter of said circular exit of the funnelled passage and the internal diameter of the supported substantially cylindrical cathode.

12. In a cathode assembling machine having 'a com veyor for supplying cathode sleeves and a stationary sleeve support, a transfer mechanism for carrying cathode sleeves individually from said supply conveyor to said support comprising a pair of jaws for gripping a cathode sleeve delivered by said conveyor, a spring for closing said jaws and mechanism for opening said jaws, and means for reciprocating said jaws to and from said st-a= tionary sleeve support including a spring urging said jaw's' toward said support whereby a minimum of mass is fixed to said jaws and accompanies a sleeve during transfer toward said support.

References Cited in the tile of this" patent UNITED STATES PATENTS Schneider et al. Feb. 21 1950' 

